A small provision in the upcoming transportation bill could fuel a big brawl between restaurant owners and opponents of drunken driving.

Both chambers are expected to introduce reauthorization bills this week with financial incentives for states to require that convicted drunken drivers use ignition interlocks — devices that require drivers to blow into a tube to test their blood-alcohol level. Congress has used similar incentives in the past to encourage states to enact mandatory seat belt safety laws.

The inclusion of this safety provision in the transportation bill is a major victory for Mothers Against Drunk Driving, the advocacy group that has spent decades pressing Congress for stricter drunken-driving laws.

But the move is strongly opposed by the American Beverage Institute, which represents more than 8,000 restaurants and chains across the country and has pledged to wage an advertising campaign against the interlock incentives.

“It would eliminate people’s ability to have a glass of wine at dinner or a beer at a ballgame and drive home,” said Sarah Longwell, the institute’s managing director. A MADD spokesman refuted that claim, saying the interlocks would apply only to offenders and would not affect casual drinkers who stay below legal consumption limits.

Longwell said her group has thrown most of its resources into this fight because restaurants stand to lose a major source of revenue if the nation’s drinking culture shifts. The institute draws in about $1.4 million each year, according to its most recent tax filings.

Fifteen states already require ignition interlocks for offenders convicted of driving under the influence of alcohol. If passed, the federal incentive program would likely pressure more states to follow suit.

MADD has led the advocacy push to get the provision, and spokesman J.T. Griffin said a federal law would be a big victory for his side — one that the group won’t give up without a big fight.

“This is everything that MADD has worked for,” Griffin said. “We are close to achieving our goal of eliminating drunk driving, and the ignition interlock is a big part of that.”

Public records show the nonprofit spent almost $40,000 in lobbying last year, but its real power lies in the vast network of motivated volunteers it has across the country. Each year, MADD brings hundreds of family members of drunken-driving victims to Capitol Hill so that they can share their stories of personal loss with Members of Congress.

Its lobbying efforts have won over influential Members, including House Transportation and Infrastructure Chairman John Mica (R-Fla.) and Sen. Frank Lautenberg (D-N.J.), who chairs the Commerce, Science, and Transportation subcommittee dealing with surface transportation. Of course, their support doesn’t guarantee that the interlock incentives will make it into the final version of the transportation bill, which has a string of politicized issued attached to it.

Both groups have already started trading shots. Griffin said ABI’s positions were designed to “put profit ahead of public safety,” and, in a press release earlier today, Longwell accused MADD of “a long history of juking the stats to drum up support.”